IMSA Ratios, Proportions, and Percentages 2

Question 1

The ratio of red to blue marbles is 5:3. If there are 40 red marbles, how many blue marbles are there?

Accepted Answer

24

Answer

Using the proportion 5/3 = 40/x, cross-multiplying gives x = 24 blue marbles.

Question 2

A salesperson earns a 6% commission on sales. How much commission does she earn on $4,500 in sales?

Accepted Answer

$270

Answer

Commission = 0.06 × 4,500 = $270.

Question 3

Two quantities are in the ratio 7:9. If the larger quantity is 63, what is the smaller?

Accepted Answer

49

Answer

Using the proportion 7/9 = x/63, cross-multiplying gives x = 49.

Question 4

A school's enrollment increased from 800 to 920 students. What is the percent increase?

Accepted Answer

15%

Answer

Percent increase = (920 − 800) / 800 × 100 = 120/800 × 100 = 15%.

Question 5

If 3/4 of a number is 60, what is 25% of the same number?

Accepted Answer

20

Answer

The number is 60 ÷ (3/4) = 80, and 25% of 80 = 0.25 × 80 = 20.

IMSA - Intermediate Math Skill Assesment Practice Test